I didn't see a dedicated board for this, so I'm hopeful this is a good place to make feature suggestions.

Very common when I'm tweaking a sprite bounding box I'm not making any unique shapes. All I really need is to tweak any edges a pixel in a direction. Instead of clicking a vertex, entering the new X and Y coordinate and repeat, how about this:

Select an edge, and displace with arrow keys by 1 pixel. Hold shift to change the increment to 5 pixels. It may also be relevant to have Control change increment to 0.1 pixels.